Agreement (Concord)
Latin glues sentences together with agreement: words that belong to the same idea share grammatical features. Caesar and Servīlius are plural together, cōnsulēs creantur Caesar et Servīlius — "Caesar and Servilius are elected consuls."
There are four classic concords: subject and verb (person, number), noun and adjective (gender, number, case), relative and antecedent (gender, number — case from its own clause), and apposition (case).
Most of the time agreement is mechanical. The trap is when sense fights with form — pars certāre parātī, "part [of them] ready to fight," where a singular collective takes a plural participle.
That's synesis, "agreement by sense," and Latin reaches for it more often than students expect.
Latin's four agreement rules — what shares features with what.
Synesis lets sense override form: collective nouns can take plural verbs, and mixed-gender subjects pick gender by who/what is meant.
See It In Action
— B. C. iii. 1
Two singular subjects pull the verb into the plural, and the predicate noun cōnsulēs matches in number too — concord cascades through the whole clause.
— Aen. v. 108
Pars is grammatically singular feminine, but parātī is masculine plural — synesis. The participle agrees with the men inside the collective noun, not the noun itself.
— Liv. xxi. 50
Mixed genders (rēx masc., classis fem.) but Livy treats both as living agents, so the predicate participle defaults to masculine plural — the "living-beings" rule of A&G § 287.
— Arch. 4
Apposition normally copies case, but a common noun appositive to a locative slips into the ablative — the one famous exception worth memorizing.
Translate the collective with its implied plurality: "a part [of them] were…"
multitūdō convictī sunt = "a multitude were convicted" (Tac. Ann. xv. 44)
The participle reveals who the collective stands for; render that group in English
pars certāre parātī = "part [of the men] ready to fight"
Predicate adjective goes masculine plural — translate naturally as "both were…"
uxor deinde ac līberī amplexī = "his wife and children embraced him"
Predicate adjective goes neuter plural — render as the abstract pair
labor voluptāsque ... iūncta sunt = "labor and delight are bound together"
Most of the time the adjective copies its noun's gender and number. With collective nouns and mixed subjects, Latin sometimes follows the meaning instead.
Adjective matches the noun's actual gender/number
māgna pars
a large part (sg. fem., as written)
Adjective matches the people/things implied
māgna pars raptae
a large part [of the women] were seized
Tip: Ask: is the noun a collective (pars, turba, multitūdō) or a mixed-gender list? If yes, expect the adjective or verb to follow the SENSE — usually plural, gender from the implied people.
In Vergil's pars certāre parātī (Aen. v. 108) — "part ready to fight" — parātī is masculine plural while pars is feminine singular. What's going on?
Study Tips
- •Memorize the Four Concords as a single mental checklist — subject/verb, noun/adjective, relative/antecedent, apposition — and run through them whenever a sentence won't parse.
- •When a singular collective noun (pars, multitūdō, turba) takes a plural verb or participle, don't 'correct' it — it's synesis and it's deliberate.
- •With mixed-gender subjects, expect masculine for people, neuter for things, and the closer-noun rule when an attributive sits in front. Look at the verb to decide.
- •Apposition almost always copies case (Cicerō, ōrātor) — but locatives flip to the ablative (Antiochīae, celebrī urbe). Keep that exception in your back pocket.